RUVBL1 and Scleroderma Polymyositis Overlap Syndrome: In contrast, several other autoantibodies (not included in the SSc 2013 ACR/EULAR criteria), such as anti-PM/Scl, -Ku, -U1-RNP, -U3-RNP, - RuvBL1/2, -SMN, have been specifically associated with scleromyositis.